Wear resistant carriage guide rail for typewriters or like machines and method of forming same



Jan. 16, 1951 H J HART 2,538,686

WEAR RESISTANT CARRIAGE GUIDE RAIL FOR TYPEWRITERS OR LIKE MACHINES AND METHOD OF FORMING SAME Filed Jan. 14, 1949 11 J0 J1 'an' Fig.5.

Patented Jan. 16, 1951 WEAR RESISTANT CARRIAGE GUIDE .RAIL FOR 'TYPEWRITERS on LIKE. MACHINES AND METHOD OF FORMING SAME Henry J. Hart, West Hartford, Conn'gassignor to Royal Typewriter Company, Inc., New York,

N. 31;, a corporation of New York I Application J anuary '14, 1949, Serial No. 163384 This invention relates to improvements'in wear resistant carriage guide railsfor typewriters or like machines and to methods of forming such rails. V

In many modern typewriters, andother' oflice machines, in which minimizingof weight is important, structural parts such as carriage sup: porting or guiding rails are formed of light weight material, for example, aluminum or magnesium alloys. Such materials do not ordinarily have good wearing or low friction qualities. Metallurgically treating or preparing carriage guiding or supporting rails to give them W friction and improved wearing properties is expensive.

An object. of the present invention is to provide a typewriter or likemachine carriage rail structure including a rail proper which may be formed of material best suited'for structural purposes, having regard to lightness and strength, and a facing in the form of a strip having lowfriction and long wearin properties applied to or assembled with the rail proper in a new, inexpensive,

and improved manner. 7

More particularly, an object, of the invention is to prepare a guide rail structure of the general character referred to, in which the facing strip is springy and pre-bowd, and is so connected to the rail proper that the inherent spring characteristics of the strip cause it to hug or lieclosely in contact with the rail proper.

A further object of the invention is to provide a new and improved method of producing a guide rail structure having a wear-resistant, low "fric tion facing.

Other objects will become apparent from a reading of the following description, the appended' claims, and the accompanying drawings, in

which:

Figure 1 is a fragmentary, vertical end-to-end sectional view of parts at the rear of a type writer embodying the invention, carriage supporting and guiding rails being shownyin elevation; I

Figure 2 is a transverse section on the line 2-2 of Figure 1; I p 1 Figure 3 is a detail rear elevational view of one end of a bottom rail, and facing strip, the parts being shown at an intermediate assembly stage; and i Figure 4 is a fragmentary detail, perspective view of one end of the facing strip, drawn on an enlarged scale and showing how it is formed for attachment to a carriage supporting rail.

7 Claims. (01. 197-69) The" invention may be embodied in or practiced in the manufacture of various oflice machines, for example, typewriters, calculators, and

The conventionalrparts shown include a part of the typewriter stationary main frame element A, and end plates BB forming part of a carriage element. Mounted on the frame A, in the usual manner, is .a bottom rail-like part I, equipped with a grooved insert 2, forming a track for ball bearings 3. .rrne carriage element includes a top rail-like .part 4 equipped with a grooved insert 5 adapted to roll on the ball bearings 3,, and thus support the carriage. for letter spacing and return travel on the frame. For keepingthe ball bearings 3 properly spaced along the tracks 2 and '5, each ball is equipped with a toothed-ring B which meshes with rack teeth I on the carriage supporting rails l and 4 re spectively. e

- The bottom rail I is formed with a rearwardly extending overhanging ledge or guide part 8, the bottom face of which cooperates with .retainers or clamp parts 9 on-the carriage for preventing the carriage from moving upwardly with respect to the bottom, frame-supported rail i. As is customary in Royal typewriters, the clamp parts 9 are formed with inclined slots in which receive screws II for securing the parts 9 to the top rail *4 in adjusted positions'with the horizontal bottom parts 9 of the parts 9 extending under'the ledge 8 with proper operating clearance. "In accordance with the present invention, a rail or rail-like member for supporting or guiding the carriage to travel on the frame is provided in a novel manner with a facing of wearresistant material having a suitably low coefiicient of friction. In the form shown the facing is applied in the -form of a strip 0 of tempered spring steel, connected at its opposite ends to the'bottom rail proper I, the inherent spring characteristics causing the strip to hug ojr lie flatly against the bottom of the ledge 8 without sagging, even though ,no means for attaching the strip C to the ledge 8 be employed between the ends of the strip.

In the .preferred manner of assembling the strip 0 to the rail proper I, the strip is prebowed to the form shown in Figure 3 and tem pered so as to give it an inherent resiliency or 3 springiness. The extreme end portions, which will not be subject to wear, are then annealed and bent to form attaching ears I2 in which openings l3 are then formed.

The strip is then placed with its outer or convex face against the bottom of the ledge 8, one end of the strip is attached'to the rail! by a screw M, as shown in Figure 3; the strip is rolled out in flat form against the bottom of the rail ledge.

8, and the opposite strip end is then connected to the rail l by a screw I4, as shown in Figure 1.

Because of its inherent spring characteristics, the strip will press against the bottom of the ledge 8 between the opposite ends of the strip, which are the only parts of the strip requiring positive attachment to the rail 1. The strip will constantly tend to re-assume a bowed condition in which the face of the strip which contacts the ledge 8 in assembly would be convex again. It is this persisting tendency of the strip to reassume its pre-bowed condition which prevents sagging and maintains the strip permanently in intimate face-to-face contact with the rail-like part I.

-A preferred structural embodiment of the invention and a preferred method of producing the novel structure have been shown and described by way of example, it being intended that the description be illustrative rather than definitive of the invention. The invention is defined in the claims.

I claim: 1. In a typewriter or like machine, a frame element; a travelling carriage element; and

means for mounting and guiding said carriage element to travel on said frame element, including a rail-like part on one of said elements, a wear-resisting strip of springy material anchored at its Opposite ends to said rail-like'part and. lying in face-to-f'ace contact with said rail-like part, said strip having an inherent spring tendcncy to assume a bowed condition which makes said strip hug said rail-like part in intimate contact therewith continuously from one point of strip anchorage to the other, and a part on the other of said elements movable along and in contact with said strip.

2. In a typewriter or like machine, a frame element; a travelling carriage element; and means for mounting and guiding said carriage element to travel on said frame element, including' a rail-like part on one of said elements, a ir ear resisting strip of springy material anchored at its opposite ends to said rail-like part and lying in face-to-face contact with said rail-like part,- said strip having an inherent spring characteristic tending to make said strip assume a bowed condition in which the face thereof which contacts said rail-like part would be convex. and apart on the other of said elements movable along. and in contact with said strip.

. 3. In a typewriter or like machine, a frame; a travelling carriage; and means for mounting and guiding said carriage to travel on 'said frame including a rail-like part on said frame, a wear 4 resisting strip of springy material anchored at its opposite ends to said rail-like part and lying in face-to-face contact with said rail-like part, said strip having an inherent spring tendency to :assume a bowed condition which makes said strip hug said rail-like part in intimate contact there- -.With continuously fromone pointof strip anchorage to the other, and a part on said carriage movable along and in contact with said strip.

4. In a typewriter or like machine, a frame; a

travelling carriage and means for mounting and guiding said carriage to travel on said frame including a rail on said frame having a track on its top anda guide part on its bottom, rolling means for supporting said carriage to travel on said track, a wear-resisting strip of springy material anchored at its opposite ends to said guide part and lying in face-to-face contact therewith, said strip having an inherent spring tendency to assume a bowed condition which makes said strip hug said guide part in intimate contact therewith continuously from one point of strip anchor age to the other, and a part on said carriage e'xtending under said strip for movement in contact therewith.

p 5. A rail structure for supporting the travelling carriage of a typewriting or like machine com prising a rail proper, and a wear-resisting strip of springy material anchored at its opposite ends to said rail proper and lying in face-to-face contact therewith, said strip having an inherent spring tendency to assume a bowed condition making it hug said rail proper intimately between the anchored ends of the strip.

6. A rail structure for supporting the travelling carriage of a typewriting or like machine comprising a rail proper, and a wear-resisting strip of springy material anchored at its oppositeends to said rail proper and lying in face-to-face contact therewith, said strip having an inherent spring characteristic tending to make said strip assume a bowed condition in which the face thereof which engages said rail proper would be convex. I

7. In a method of providing a typewriter or like machine rail with a wear-resistant elongated guide surface, forming a tempered, springy. bowed strip of wear-resistant material; applying said strip to said rail with the convex'face of the strip against the rail; and anchoring the ends of the strip to the rail, whereby the inherent spring characteristics of the strip, when its ends are so anchored, will cause said strip to hug said rail in inimate contact therewith throughout the length of the strip.

HENRY J. HART. I

REFERENCES CITED The folowing references are ofrecord in the file of this patent:

v UNITED STATES PATENTS Number I Name Date 1,245,324.v Droitcour Nov..6.,;l9l7 

